Stocks are on a winning streak. The Dow, S&P 500, and Nasdaq indexes all closed at record highs on Friday.

The day before, they did the same thing — along with the Russell 2000, an index of small-cap stocks that hadn’t hit a new high before that for four years. (The Russell 2000 closed down 0.77% on Friday.)

Everything that can go up can go down; we know this. And there’s still a lot of uncertainty out there for investors about tariffs and interest rate policy.

But there are some reasons to think the bulls may stick around for a while.

It’s economic fundamentals that are now driving stocks higher, according to Scott Wren, senior global equity strategist at the Wells Fargo Investment Institute.

“The market doesn’t think there’s going to be a recession,” he said. “GDP estimates are going up. Earnings estimates have gone up.”

For small-cap stocks in particular, it’s a welcome moment in the sun, said Jed Ellerbroek, portfolio manager at Argent Capital Management.

“For the last decade, U.S. large-cap stocks have beaten U.S. small-cap stocks by quite a bit,” he said.

The Fed starting to lower interest rates, he added, will be especially helpful for smaller companies, as they tend to have more debt.

Bull markets can end with everyone piling in, stocks getting overvalued, and investors getting burned. But Wells Fargo’s Scott Wren doesn’t see much risk of that — so far.

“You know, our clients still have a considerable amount of cash in their accounts that — they’re not selling stocks, but they’re not jumping in, either,” he said.

“The mood does not seem euphoric,” said Sam Stovall, chief investment strategist at CFRA Research. “I think that’s a good sign. There’s not too much expectations that share prices will continue to set new highs. And as a result,” they probably will.